1. Field of the Invention
The invention relates to an arrangement for spacing electrodes used in electrolytic processes.
2. Description of the Prior Art
In the electrowinning of copper, anodes and cathodes are suspended side-by-side in a processing tank with anodes and cathodes alternating. The tank contains an electrolytic bath, and copper is deposited on the major faces of the cathodes in the form of sheets. The sheets are stripped from the cathodes once they have achieved a predetermined thickness.
A separation must be maintained between an anode and its neighboring cathodes as well as between an anode and an adjoining wall of the processing tank. To this end, a hole is drilled in each anode. A threaded shaft carrying a button at one end is passed through the hole in the respective anode so that the button comes into contact with one of the major surfaces of the anode. Subsequently, a second button with a threaded passage is screwed onto the shaft and comes to rest against the opposite major surface of the anode. Each of the buttons is nonconductive and lies between the anode and a neighboring cathode or between the anode and a wall of the processing tank.
The cathodes are removed from the tank in order to strip the copper sheets from them. Following stripping of the copper sheets, the cathodes are reinserted in the tank. On occasion, a cathode is lowered onto one of the buttons mounted on the adjoining anodes. When this happens, the button can shear off.
Another difficulty with the buttons is that they reduce the amount of current reaching the areas of the cathodes directly opposite the buttons. This decreases the amount of copper deposited in these areas and leads to shadowing.
U.S. Pat. No. 4,619,751 addresses these difficulties. This patent discloses a spacer which is designed to slide on the header bar of an anode. The spacer has a length which exceeds the height of the anode, and the spacer includes two cylindrical legs which sit on opposite sides of the anode. The lower ends of the legs are joined to one another by a U-shaped part or a pin which passes underneath the anode while the upper ends of the legs are joined to each other by an inverted V-shaped part which passes over the header bar. The inverted V-shape of the upper part of the spacer reduces the likelihood of a cathode catching on the spacer as the cathode is lowered into position next to the anode. Moreover, the cathode can slide along the sloping surfaces of the inverted V-shaped part of the spacer to facilitate lowering of the cathode. Finally, the cylindrical shape of the spacer legs reduces the contact area between a leg and an adjoining cathode.
The spacer of the above patent operates satisfactorily. However, as mentioned previously, the spacer has a length which exceeds the height of an anode. Consequently, the spacer is rather large and unwieldy.
It is an object of the invention to provide a spacing arrangement for electrodes which is relatively easy to handle.
The preceding object, as well as others which will become apparent as the description proceeds, are achieved by the invention.
One aspect of the invention resides in an arrangement for spacing electrodes.
One embodiment of the arrangement comprises at least one electrode having a first side, an opposite second side and an opening extending between the first side and the second side. This embodiment of the arrangement further comprises at least one spacer passing through the opening in the electrode. The spacer has an upper end provided with a confining part which is at least partially disposed on the first side of the electrode, and the spacer also includes a spacing part which is at least partially disposed on the second side of the electrode to separate the latter from a neighboring electrode. The confining part has a first surface portion which faces one side of the electrode, an upward facing second surface portion and an upward facing edge which bridges the first surface portion and the second surface portion. The edge at least approximates a knife-edge, and the second surface portion has a slope to permit sliding of an electrode along the second surface portion.
The preceding embodiment of the spacing arrangement includes a spacer which can be mounted in an opening of an electrode. Since such an opening can be formed at a location below the upper end of the electrode, it is not necessary for the spacer to extend along the full height of the electrode. This allows the size of the spacer to be reduced and handling of the spacer to be simplified.
Due to the fact that the upward facing edge of the confining part of the spacer at least approximates a knife-edge, an electrode lowered onto the spacer is highly unlikely to become hung up on the edge and cause the spacer to shear. Thus, the area of the edge will generally be too small for an electrode to catch on the edge. Furthermore, since the upward facing second surface portion adjoining the upward facing edge of the confining part has a slope, an electrode lowered onto the second surface portion can slide so that there is little likelihood of the lowered electrode being hung up by the second surface portion.
Another embodiment of the arrangement comprises a first spacer adapted to be mounted on a selected electrode of a plurality of electrodes and a second spacer adapted to be mounted on the selected electrode. The first spacer defines a first space while the second spacer, which is discrete from the first spacer, defines a second space. The first spacer and the second spacer are arranged with a portion of the first spacer in the second space and a portion of the second spacer in the first space.
The present embodiment of the spacing arrangement includes two distinct spacers which are adapted to be mounted on an electrode. The spacers have cooperating portions which make it possible to assemble the two spacers so that they can function as a single spacer. Since the two spacers are distinct, however, each of these spacers can be smaller than such a single spacer thereby allowing the two spacers to be manipulated with relative ease.
An additional aspect of the invention resides in a method of arranging for the spacing of electrodes.
One embodiment of the method comprises the steps of providing at least one electrode having a first side, an opposite second side and an opening extending between the first side and the second side, and providing a spacer having a spacing part and an end which includes a confining part. The confining part has a first surface portion, a second surface portion and an edge which bridges the first surface portion and the second surface portion. Such edge at least approximates a knife-edge, and the second surface portion has a slope. This embodiment of the method further comprises the step of passing the spacer through the opening in the electrode so that the confining part is at least partially disposed on the first side of the electrode and the spacing part is at least partially disposed on the second side of the electrode. The instant embodiment of the method also comprises the step of positioning the spacer with the first surface portion facing the first side of the electrode and with the second surface portion and the knife-edge facing upward. The current embodiment of the method additionally comprises the steps of immersing the electrode and the spacer in an electrolytic bath, and immersing an additional electrode in the electrolytic bath such that the spacing part is disposed between the electrodes.
Another embodiment of the method comprises the steps of providing a first spacer which defines a first space and is adapted to be mounted on a selected electrode of a plurality of electrodes, and providing a discrete second spacer which defines a second space and is adapted to be mounted on the selected electrode. This embodiment of the method further comprises the step of positioning the first spacer and the second spacer with a portion of the first spacer in the second space and with a portion of the second spacer in the first space.
Additional features and advantages of the invention will be forthcoming from the following detailed description of preferred embodiments when read in conjunction with the accompanying drawings.